Graeme Clark and Emma Johnston write in The Conversation (20.9.18) about their research into the operation and environmental impact of desalination plants, which indicates that pumping very salty water into the ocean has surprisingly little impact on marine life.
'Millions of people all over the world rely on desalinated water. Closer to home, Australia has desalination plants in Melbourne, Adelaide, Perth, the Gold Coast, and many remote and regional locations.
'But despite the growing size and number of desalination plants, the environmental impacts are little understood. Our six-year study, published recently in the journal Water Research, looked at the health the marine environment before, during and after the Sydney Desalination Plant was operating.
'Our research tested the effect of pumping and “diffusing” highly concentrated salt water (a byproduct of desalination) back into the ocean.
'Contrary to our expectation that high salt levels would impact sea creatures, we found that ecological changes were largely confined to an area within 100m of the discharge point, and reduced shortly after the plant was turned off. We also found the changes were likely a result of strong currents created by the outfall jets, rather than high salinity.
'... There is a rapid expansion of the use of desalination, with global capacity increasing by 57% between 2008 and 2013. Our results will help designers and researchers in this area ensure desalination plants minimise their effect on local coastal systems.'